Films of indium-tin oxide (ITO) were deposited. by ion-beam sputtering. Two types of seed layers. of ITO were deposited prior to bulk-layer deposition. The types of seed layers were determined by ion species, namely, either pure Ar+ or a mixture of Ar+ and O-2(+). The microstructure and the preferred orientation of the bulk films mimicked those, of the seed layer. Films with larger grains were obtained when the seed layer was used. The electron mobility did not depend on the type of microstructure. The ability to control the microstructure without sacrificing the electrical conductivity was demonstrated. (C) 2003 American Vacuum Society.